Adapt online product designer for our products

We are a company making bespoke house signs for our website visitors. We have purchased an online design tool which is an addon for woocommerce. in general the tool works quite well but we need a few customizations to the tool to make it suitable for our product ranges. We contacted the original software develover who is located in Vietnam. Unfortunately due to the language barrier he does not understand our brief and we don't understand his answers. We have decided to offer this customization to a freelancer who has a good knowledge of java scripts, json and SVG and these are the elements the script are built with. Please take a look at our test website: [login to view URL] . We need several changes to the scripts to make it user friendly for our visitors.. [login to view URL] modifications to the UI to make it easier for the visitor to use the tool, [login to view URL] modification to add an interactive 'help' feature in the UI 3. Modification to the way the SVG fonts are anchored to set sized oval paths for arching text on our oval signs - [login to view URL]:14711125271268115401:73:000000:37 Please only contact us if you have experience in SVG, Json, HTML5, and writing java scripts for graphics. The original script purchased from [login to view URL] as an addon to woocommerce. We want to keep this shopping cart functionality and modify the functionality of some of the existing features. We have budgeted around 500USD for the complete job If you think you can help please contact me with any further questions you need to know